CODEWITHSUNDEEP
c++boostandroid-ndkcmakejava-native-interface
ntoskrnl
ntoskrnl

Reputation: 43

Android NDK cmake and dependent libraries

I'd like to use a library (source codes from GH) in my JNI code. But the library depends on two other libraries (NTL and Boost) that are not available in Android NDK. Now I am a bit confused and not sure if I understand correctly my following actions.

  1. C++ code for Android is built into shared libraries (.so) for every platform (x86_64, armv7..). Does this mean that NTL, Boost and the lib I want to use must be compiled by me from source codes for these platforms too? If yes, how to do it correctly with cmake?

  2. If I should build all the libs for specific platforms, how it is better to do, either as static libs (.a + headers) or as shared libs?

  3. Do I really need to build NTL and Boost for all the platforms or I should do it just for the needed library?

  4. Is Android.mk file required or can help with cmake? As I understand, it is used with "ndk-build" only.

Generally, if this sequence of actions is correct?

  1. Build NTL for all platforms (.a + headers)
  2. Build Boost for all platforms (.a + headers)
  3. Build Library for all platforms (.so)
  4. Add Library's .so-file as a dependency in CMakeLists for JNI project. (Do I still need dependent libs and headers or that dependencies will be incapsulated into lib?)

Upvotes: 4

Views: 750

Answers (1)

Dan Albert
Dan Albert

Reputation: 10499

C++ code for Android is built into shared libraries (.so) for every platform (x86_64, armv7..). Does this mean that NTL, Boost and the lib I want to use must be compiled by me from source codes for these platforms too? If yes, how to do it correctly with cmake?

Yes, you'll need to build those libraries from source (or find a binary distribution for Android) if you want to use those libraries in your application. As for how to do that, you'll have to wait for someone else to answer or try Googling it. There are a handful of "how to build X for Android" tutorials out there, but I don't know if you'll find many for CMake since CMake is pretty new for Android.

If I should build all the libs for specific platforms, how it is better to do, either as static libs (.a + headers) or as shared libs?

That mostly depends on how many shared libraries you're building for your app. The ideal model for an app is to use a single shared library in your app and statically link in all of your dependencies (going to avoid linker bugs on old versions of Android, and will make your app as small as possible). If you have multiple shared libraries for your code, you'll need to use shared libraries for your dependencies to avoid ODR issues.

Do I really need to build NTL and Boost for all the platforms or I should do it just for the needed library?

You'll need to do it for any platform you need to use those libraries on.

Is Android.mk file required or can help with cmake? As I understand, it is used with "ndk-build" only.

CMake and ndk-build should both work, but you might have an easier time finding porting instructions for ndk-build due to CMake's relative youth in Android.

Upvotes: 2

Related Questions